.presentation {
	position:relative;
}

img#presentation_img {
	height:auto;
	display:block;
	position:absolute;
	top:0;
	left:0;
	right:0;
	bottom:0;
	z-index:10;
	cursor:pointer;
	border-radius:6px;
	width:100%;
	height:auto;
}

iframe#presentation_video {
	display:block;
	position:absolute;
	width:100%;
	height:100%;
	top:0;
	right:0;
	bottom:0;
	left:0;
	z-index:9;
	cursor:pointer;
	opacity:0;
}